Since the Pony Car era was just taking hold thanks to Mustang in 1964, Barracuda in 1965 and the Camaro-Firebird in 1967, the mid-size muscle car was the “in” thing, as most of the muscle cars back then rode on wheelbases of 115 to 117 inches. The 67 GTX came with a 116-inch wheelbase in the Satellite line, (along with sister Dodge Coronet R/T), with power coming from a 440 inch “Super Commando” 375-horsepower V8 hooked to either a 4-speed manual or the popular Torqueflite 3-speed automatic.

The only GTX engine option available was an $800 fire breathing 426 Hemi, complete with two four barrels and a de-tuned rating of just 425 horsepower. The street and strip crowd quickly figured that with a good set of headers, some ignition work, low ratio rear (4:10 or 4:56), the Hemi was an easy 11-second quarter-mile car with few if any foes.

The 440, however, was the more popular power plant thanks to a hydraulic cam and single four-barrel induction, which made for easier tuning and much better streetability. However, the same bolt on changes made a 440 GTX very fast, capable of 12-second quarter miles with 3:90 gearing.

So popular was the GTX that Plymouth expanded its muscle car program to include the 1968 Road Runner, a stripped down, cheaper version of the better appointed “Gentleman’s Muscle Car” the GTX came to be known as.

Built in St. Louis, Mo. the GTX would have a run of just five years, ending in 1971 and suffering declining sales in the face of new government regulations on emissions and the rise in gasoline prices. The recipe that worked when fuel was 33-cents per gallon and GTX delivered eight MPG average was no longer valid, and Plymouth, along with other manufacturers, put an end to the muscle car heyday with more efficient “sporty” models.

The GTX may be gone, but this model will live on as a muscle car that really did make a difference. Today, a Hemi GTX matching number car is worth in the $150,000 neighborhood, while the 440 models can fetch in the $60,000 range in top condition.